The invention concerns a drive for turning a pinion shaft provided with toothed ridges by means of a rack, which is connected on both sides with pistons, which in each case are held in a cylinder with the formation of a working space upon which a pressure medium acts and which may be closed by a cover or piston.
EP-A 0 476 208 concerns an arrangement for turning, for example, workpieces to be finished on a carrier, which may be turned by means of a pinion shaft with toothed ridges via a rack. In this case the rack is to be mounted in a cylinder bore of a housing. It is essential that the distance from teeth and pinion shaft, respectively toothed ridge, may be changed, which is performed by adjusting lateral play of a pin on the rack, against which pin a threaded pin bears. In order to make the adjustment the rotary drive must be stopped, after which manual adjustment is performed by means of a screwdriver or the like.
On the other hand, the task of the present invention is to develop a drive of the above-mentioned type, in the case of which automatic elimination of the play between the teeth of the rack and the toothed ridges of the pinion shaft takes place at least in the end positions.